In Reply to: Standby switch...pros and cons? posted by DAK on August 18, 2016 at 13:52:01:
Then you can have a low voltage switch to turn on the high voltage. Or better yet a timer circuit and no switch to worry about. Since the MOSFET or SCR is hard on, you don't need much heatsinking either as you would in a series pass regulator.
Don't get caught up in the "sand sound" debate. The MOSFET will have 3 ohms or less on resistance. How is that an issue at 300v+ ? Likewise an SCR will drop 0.7 volts - not an issue either. And this is not a series pass regulator application where the output impedance varies. A solid state B+ switch will impart "no sonic signature" or other audiophile ills.
One caveat with an SCR, you can't turn the HV back off with the "HV switch" once it's turned on. Ypu must power down the amp to break the current flow through the SCR to turn it off - basic SCR theory.
Another plus of the SCR is you could use a momentary switch. Once latched, the SCR stays on. That was you can;t accidentally leave the B+ switch on when the whole amp is turned off.
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Follow Ups
- Use a MOSFET or SCR - gusser 11:15:05 08/19/16 (8)
- RE: Use a MOSFET or SCR - DAK 11:22:32 08/19/16 (7)
- No gain. - gusser 11:28:42 08/19/16 (6)
- Not only that, - Michael Samra 22:26:03 08/19/16 (0)
- RE: If i add more C i can increase the B+ - DAK 11:56:14 08/19/16 (4)
- Yes - gusser 12:06:25 08/19/16 (3)
- RE: Yes - Tre' 18:42:45 08/22/16 (0)
- RE: Capacitance would increase from 200 to 205 uf - DAK 13:07:29 08/19/16 (1)
- RE: Capacitance would increase from 200 to 205 uf - Ed Sawyer 13:14:46 08/19/16 (0)